erlang: -module/M:F cross-module calls (+10 tests)

lib/erlang/runtime.sx

@@ -742,3 +742,75 @@
     (er-proc-set! target :exit-result nil)
     (er-proc-set! target :continuation nil)
     (er-propagate-exit! target reason)))
+
+;; ── module registry ─────────────────────────────────────────────
+;; Global mutable dict from module name -> module env (which itself
+;; binds each function name to a fun value capturing the same env, so
+;; sibling functions can call each other recursively).
+(define er-modules (list {}))
+(define er-modules-get (fn () (nth er-modules 0)))
+(define er-modules-reset! (fn () (set-nth! er-modules 0 {})))
+
+;; Load an Erlang module declaration. Source must start with
+;; `-module(Name).` and contain function definitions. Functions
+;; sharing a name (different arities) get their clauses concatenated
+;; into a single fun value — `er-apply-fun-clauses` already filters
+;; by arity, so multi-arity dispatch falls out for free.
+(define
+  erlang-load-module
+  (fn
+    (src)
+    (let
+      ((module-ast (er-parse-module src)))
+      (let
+        ((mod-name (get module-ast :name))
+          (functions (get module-ast :functions))
+          (mod-env (er-env-new))
+          (by-name {}))
+        (for-each
+          (fn
+            (i)
+            (let
+              ((f (nth functions i)))
+              (let
+                ((name (get f :name)) (clauses (get f :clauses)))
+                (if
+                  (dict-has? by-name name)
+                  (let
+                    ((existing (get by-name name)))
+                    (for-each
+                      (fn (j) (append! existing (nth clauses j)))
+                      (range 0 (len clauses))))
+                  (let
+                    ((init (list)))
+                    (for-each
+                      (fn (j) (append! init (nth clauses j)))
+                      (range 0 (len clauses)))
+                    (dict-set! by-name name init))))))
+          (range 0 (len functions)))
+        (for-each
+          (fn
+            (k)
+            (let
+              ((all-clauses (get by-name k)))
+              (er-env-bind! mod-env k (er-mk-fun all-clauses mod-env))))
+          (keys by-name))
+        (dict-set! (er-modules-get) mod-name mod-env)
+        (er-mk-atom mod-name)))))
+
+(define
+  er-apply-user-module
+  (fn
+    (mod name vs)
+    (let
+      ((mod-env (get (er-modules-get) mod)))
+      (if
+        (not (dict-has? mod-env name))
+        (raise
+          (er-mk-error-marker
+            (er-mk-tuple
+              (list
+                (er-mk-atom "undef")
+                (er-mk-atom mod)
+                (er-mk-atom name)))))
+        (er-apply-fun (get mod-env name) vs)))))

lib/erlang/scoreboard.json

@@ -1,11 +1,11 @@
 {
   "language": "erlang",
-  "total_pass": 405,
-  "total": 405,
+  "total_pass": 415,
+  "total": 415,
   "suites": [
     {"name":"tokenize","pass":62,"total":62,"status":"ok"},
     {"name":"parse","pass":52,"total":52,"status":"ok"},
-    {"name":"eval","pass":221,"total":221,"status":"ok"},
+    {"name":"eval","pass":231,"total":231,"status":"ok"},
     {"name":"runtime","pass":39,"total":39,"status":"ok"},
     {"name":"ring","pass":4,"total":4,"status":"ok"},
     {"name":"ping-pong","pass":4,"total":4,"status":"ok"},

lib/erlang/scoreboard.md

@@ -1,12 +1,12 @@
 # Erlang-on-SX Scoreboard
 
-**Total: 405 / 405 tests passing**
+**Total: 415 / 415 tests passing**
 
 |  | Suite | Pass | Total |
 |---|---|---|---|
 | ✅ | tokenize | 62 | 62 |
 | ✅ | parse | 52 | 52 |
-| ✅ | eval | 221 | 221 |
+| ✅ | eval | 231 | 231 |
 | ✅ | runtime | 39 | 39 |
 | ✅ | ring | 4 | 4 |
 | ✅ | ping-pong | 4 | 4 |

lib/erlang/tests/eval.sx

@@ -634,6 +634,71 @@
   (nm (ev "try exit(a) catch error:X -> e; throw:X -> t; exit:X -> x end"))
   "x")
 
+;; ── modules: -module(M)., M:F/N cross-module calls ─────────────
+(er-eval-test "load module returns name"
+  (nm (erlang-load-module "-module(m1). foo() -> 42."))
+  "m1")
+
+(er-eval-test "cross-module zero-arity"
+  (do
+    (erlang-load-module "-module(m2). val() -> 7.")
+    (ev "m2:val()"))
+  7)
+
+(er-eval-test "cross-module n-ary"
+  (do
+    (erlang-load-module "-module(m3). add(X, Y) -> X + Y.")
+    (ev "m3:add(3, 4)"))
+  7)
+
+(er-eval-test "module recursive fn"
+  (do
+    (erlang-load-module "-module(m4). fact(0) -> 1; fact(N) -> N * fact(N-1).")
+    (ev "m4:fact(6)"))
+  720)
+
+(er-eval-test "module sibling calls"
+  (do
+    (erlang-load-module "-module(m5). a(X) -> b(X) + 1. b(X) -> X * 10.")
+    (ev "m5:a(5)"))
+  51)
+
+(er-eval-test "module multi-arity"
+  (do
+    (erlang-load-module
+      "-module(m6). f(X) -> X. f(X, Y) -> X + Y. f(X, Y, Z) -> X * Y + Z.")
+    (ev "{m6:f(1), m6:f(2, 3), m6:f(2, 3, 4)}"))
+  (er-mk-tuple (list 1 5 10)))
+
+(er-eval-test "module pattern match clauses"
+  (do
+    (erlang-load-module
+      "-module(m7). check(0) -> zero; check(N) when N > 0 -> pos; check(_) -> neg.")
+    (nm (ev "m7:check(-3)")))
+  "neg")
+
+(er-eval-test "cross-module call within module"
+  (do
+    (erlang-load-module "-module(util1). dbl(X) -> X * 2.")
+    (erlang-load-module "-module(util2). quad(X) -> util1:dbl(X) * 2.")
+    (ev "util2:quad(5)"))
+  20)
+
+(er-eval-test "module undefined fn raises"
+  (do
+    (erlang-load-module "-module(m8). foo() -> 1.")
+    (er-io-flush!)
+    (ev "P = spawn(fun () -> m8:bar() end), receive after 0 -> ok end")
+    (let ((reason (er-proc-field (er-mk-pid 1) :exit-reason)))
+      (and (er-tuple? reason) (nm (nth (get reason :elements) 0)))))
+  "undef")
+
+(er-eval-test "module function used in spawn"
+  (do
+    (erlang-load-module "-module(m9). work(P) -> P ! done.")
+    (ev "Me = self(), spawn(fun () -> m9:work(Me) end), receive done -> ok end"))
+  (er-mk-atom "ok"))
+
 (define
   er-eval-test-summary
   (str "eval " er-eval-test-pass "/" er-eval-test-count))

lib/erlang/transpile.sx

@@ -479,7 +479,12 @@
       ((fun-node (get node :fun)) (args (get node :args)))
       (cond
         (= (get fun-node :type) "atom")
-        (er-apply-bif (get fun-node :value) (er-eval-args args env))
+        (let
+          ((name (get fun-node :value)) (vs (er-eval-args args env)))
+          (cond
+            (and (dict-has? env name) (er-fun? (get env name)))
+            (er-apply-fun (get env name) vs)
+            :else (er-apply-bif name vs)))
         (= (get fun-node :type) "remote")
         (er-apply-remote-bif
           (get (get fun-node :mod) :value)
@@ -584,6 +589,8 @@
   (fn
     (mod name vs)
     (cond
+      (dict-has? (er-modules-get) mod)
+      (er-apply-user-module mod name vs)
       (= mod "lists") (er-apply-lists-bif name vs)
       (= mod "io") (er-apply-io-bif name vs)
       (= mod "erlang") (er-apply-bif name vs)